Yeast Two Hybridization Analyses of Atlantic Salmon Sdy Interactions

The gene encoding sexually dimorphic on the Y chromosome (sdY) is the sex-determining gene in rainbow trout and it has been hypothesized that it is involved in sex-determination in Atlantic salmon. Unlike many other sex-determining gene products, sdY does not appear to contain a DNA binding domain and thus is unlikely to be a transcription factor. In order to elucidate the sex-determining pathway in Atlantic salmon we used the yeast two-hybrid system to identify proteins which interact with sdY. Two "Mate and Plate^TM" cDNA expression libraries were produced, one with sdY and the other from testis mRNA, and these were used to transform yeast strains. Subsequent mating and selection of these strains revealed that sdY interacts with itself and putatively with the 40S ribosomal protein S16 and transmembrane protein 90A, neither of which are part of a known sex-determining pathway. Although these results are very preliminary, these findings provide new insight on the role of sdY in sex-determination.